[mythtv-users] firewire card

John P Poet jppoet at gmail.com
Mon Aug 14 02:46:22 UTC 2006


I originally tried hooking up my SA3250HD to my main mythbackend
machine which has an on-board firewire controller.  While I got it to
work to a point, the resulting captures where *HEAVILY* pixelated.

I then tried hooking up the SA3250HD to my frontend machine, and
started running the backend on that machine.  Much better.  Captures
were 98% cleaner than they were with the firewire on the main backend.

Unfortunately, whenever the firewire was actively being used to
capture an HD stream, whatever I was watching would have audio
drop-outs.  Thought I had it solved at one point, by adjusting the PCI
latencies.  While adjusting the latency did seem to help, it did not
solve the problem.

The audio card in my frontend is an m-audio 410.  I decided to try my
old Sound Blaster Live! card.  Much better -- the SB Live! did not
have the drop-outs near as bad as the m-audio.

The problem with the Sound Blaster Live!, is it only understand 48KHz.
 The reason I went away from it in the first play, is playing 44.1KHz
music files did not sound as good as they should.  This was in
comparison to my Turtle Beach Audiotron.  Switching to the m-audio 410
resulted in a *very* noticeable improvement in sound quality with
44.1KHz material.

So, I had a problem.  The SB Live! was better when the firewire was in
use, but bad for music listening.  I decided to see if I could solve
my problem with hooking the firewire up to the main backend.

I figured it just had to be a cable or splitter problem with the coax.
 I ran a brand new piece of high quality Belden coax all the way from
the street, right into my office where the backend was located.  I
hooked this coax right into the SA3250HD box.  It made no difference.
Captures were still so pixelated, that it would actually cause the
test-mpeg2 app to segfault.

Only thing left that could cause the problem was the firewire port.  I
called up a friend, and asked to borrow is PCI add on card.  Problem
solved.  Wish I had done that to begin with -- running that coax took
a couple of hours!

The card I borrowed was just a generic 4-port firewire using a TI chipset.

John


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